package com.example.forum.interceptor;

import com.example.forum.config.AppConfig;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;

/**
 * 登录拦截器
 */
@Component
public class LoginInterceptor implements HandlerInterceptor {
    @Value("${bit-forum.login.url}")
    private String defaultURL;
    /**
     * 前置处理(对请求的预处理)
     * @return true : 继续流程 <br/> false : 流程中断
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws IOException {
        //获取session对象
        HttpSession session=request.getSession(false);
        if(session!=null&&session.getAttribute(AppConfig.USER_SESSION)!=null){
            //用户已经登录
            return true;
        }
        if(!defaultURL.startsWith("/")){
            defaultURL="/"+defaultURL;
        }
        //校验不通过跳转到登录界面
        response.sendRedirect(defaultURL);
        //中断流程
        return false;
    }
}
